Note: Descriptions are shown in the official language in which they were submitted.
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STABLE INJECTABLE COMPOSITION OF ALPHA TOCOPHERYL
SUCCINATE, ANALOGUES AND SALTS THEREOF
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to the field of compositions of alpha-tocopheryl
succinate, anaiogues or salts thereof. In particular, this invention provides
colloidal
dispersion compositions of alpha-tocopheryl succinate, analogues or salts
thereof
that are stable, safe and efficacious.
Description of the Related Art
The greatest challenge in anticancer therapy lies with selectivity of
the therapeutic agent; an effective anticancer drug must be highly selective
for
malignant cells while being free of deleterious efforts on normal cells.
Unfortunately, to date, most anticancer drugs, especially in the family of
chemotherapy agents, are known to possess high toxicity resulting in undesired
side effects in patients and sadly such side effects are often so severe that
they
are either intolerable by the patient, causing deterioration of general health
conditions of the patients, or negatively affect quality of life of the
patient. The
development of more selective and non-toxic therapeutic agents has become a
new trend in the pursuit of new anticancer treatments.
Great hope has been given to micronutrients as anticancer agents,
since they represent natural compounds with beneficial effects for normal
cells and
tissues. One of these is alpha-tocopheryl succinate (TS). Alpha-tocopheryl
succinate, also known as vitamin E succinate, a semisynthetic vitamin E
analogue,
has been reported to have potent anticancer activities. Compared to the
traditional
chemotherapeutic agent, alpha-tocopheryl succinate is regarded as non-toxic
(Zondlo Fiume, Int J Toxicol. 2002; 21 Suppl 3:51-116) and is metabolized to
vitamin E, thereby yielding a compound with a secondary beneficial activity.
Thus,
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alpha-tocopheryl succinate epitomizes a group of novel compounds that hold
substantial promise as future anticancer drugs.
Alpha-tocopheryl succinate is a potent anticancer agent with a
unique structure and pharmacokinetics in vivo. Alpha-tocopheryl succinate is
highly selective for malignant cells, inducing them into apoptotic death
largely via
the mitochondrial route (Neuzil, BrJ Cancer. 2003 Nov 17; 89(10):1822-6).
Many researchers have reported the anticancer activities of alpha-
tocopheryl succinate against various tumors based on in vivo or in vitro
studies.
Malafa et al. reported that alpha-tocopheryl succinate inhibited melanoma
growth
in mice (Surgery. 2002 Jan; 131(1):85-91). Barnett demonstrated the activity
of
alpha-tocopheryl succinate in inhibiting color cancer liver metastases (J Surg
Res.
2002 Aug; 106(2):292-8). In immunocompromised mice, Tomassetti has shown
that alpha-tocopheryl succinate suppressed malignant mesothelioma (IntJ
Cancer.
2004 May 1; 109(5):641-2). Liu etal. reported alpha-tocopheryl succinate
inhibits
human gastric carcinoma cell growth (Wei Sheng Yan Jiu. 2000 May 30;
29(3):172-4). All of these researchers seem to point out that alpha-tocopheryl
succinate is a potent anticancer agent against various cancer cells with high
selectivity.
The anticancer mechanism of alpha-tocopheryl succinate has also
been well studied. Most researchers suggest that alpha-tocopheryl succinate
induces apoptosis in cancer cells. Neuzil et al. published several papers on
the
study of the apoptotic mechanism of alpha-tocopheryl succinate (FASEB J. 15
(2):
403-15, 2001; Redox Rep. 2001; 6(3):143-51; Biochem J. 2002 Mar 15; 362(Pt
3):709-15).
The structure-and-apoptogenic activity relationship of alpha-
tocopheryl succinate has also been well studied. The apoptogenic activity of
alpha-tocopheryl succinate was found to be unique to the alpha-tocopheryl
succinate structure and is not related to vitamin E. Kogure et al. reported
that the
terminal dicarboxylic moiety is required for the apoptotic activity of alpha-
tocopheryl succinate (Biochim BiophysActa. 2004 May 3; 1672(2):93-9). Amongst
the analogues tested, the esters of alpha-tocopheroi with dicarboxylic acids
such
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as alpha-tocopheryl oxalate, alpha-tocopheryl malonate, along with alpha-
tocopheryl succinate, were found to induce apoptosis in mouse cancer line
(C1271), whereas the other tocopheryl analogs or esters tested including alpha-
tocopheryl pimelate, alpha-tocopheryl succinate ethyl ester, alpha-tocopherol,
gamma-tocopherol, alpha-tocopheryl nicotinate and alpha-tocopheryl acetate,
were not apoptogenic. Alpha-tocopheryl oxalate was the most potent alpha-
tocopheryl derivative tested.
Birringer et al. (BrJ Cancer. 2003 Jun 16; 88(12):1948-55) reported
a significant difference in apoptogenic activity amongst alpha-tocopheryl
succinate
analogues. Analogues of alpha-tocopheryl succinate with lower numbers of
methyl
substitutions on the aromatic ring were less active than alpha-tocopheryl
succinate. Replacement of the succinyl group with a maleyl group greatly
enhanced the activity, while replacement of the succinyl group with a glutaryl
group
reduced the activity. Methylation of the free succinyl carboxyl group on alpha-
tocopheryl succinate and delta- tocopheryl succinate completely eliminated the
apoptogenic activity of the parent compounds. Alpha-tocotrienol (alpha-T3 H)
failed to induce apoptosis, while gamma-T3 H was apoptogenic, and more so
when succinylated. Shortening the aliphatic side chain of gamma-T3 by one
isoprenyl unit increased its activity. Neither phytyl nor oleyl succinate
caused
apoptosis.
Other interesting biological findings of alpha-tocopheryl succinate
include alpha-tocopheryl succinate' ability to enhance radiation-induced
chromosomal damage levels in human cancer cells, but reduces the damage
levels in normal cells (Kumar et al., J Am Coll Nutr. 2002 Aug; 21(4):339-43),
and
to sensitize established tumors to vaccination with nonmatured dendritic cells
(Ramanathapuram etal., Cancerlmmunollmmunother. 2004; 53(7):580-8). The
safety assessment of alpha-tocopheryl succinate has also been well documented
(Zondlo Fiume, Int J Toxicol. 2002; 21 Suppl 3:51-116).
In most studies, the in vivo anticancer activity of alpha-tocopheryl
succinate was demonstrated by intraperitoneal injection (i.p.) of alpha-
tocopheryl
succinate, which is dissolved in DMSO. Intraperitoneal (i.p.) administration
of a
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therapeutic agent dissolved in DMSO is not a generally accepted procedure for
humans. Alpha-tocopheryl succinate loses its anticancer activity if it is
given orally
since the succinate ester is cleaved in the gastrointestinal tract, yielding
the parent
alpha tocopherol, which lacks the apoptogenic activity.
Therefore for human therapeutic purposes, an intravenously
injectable formulation (i.v.) of alpha-tocopheryl succinate is desired. To
date, there
appear to be only two alpha-tocopheryl succinate intravenous formulations.
Kogure et al. reported a vesiculated alpha-tocopheryl succinate formulation
that
was administered to mice intravenously (CancerLett. 2003 Mar20; 192(1):19-24).
This vesiculated alpha-tocopheryl succinate formulation contains alpha-
tocopheryl
succinate in phosphate buffered saline with pH adjusted to neutral with sodium
hydroxide. The vesiculated alpha-tocopheryl succinate formulation was prepared
by sonication and was characterized as a suspension with an average diameter
of
350 nm.
Another intravenously injectable formulation of alpha-tocopheryl
succinate (Jizomoto'et al., Biochim Biophys Acta. 1994 Aug 4; 1213(3):343-8)
is a
liposomal formulation that contains phosphatidylethanolamine and cholesterol.
This formulation was designed as a pH-sensitive drug delivery vehicle capable
of
incorporating a drug at a neutral pH and releasing the drug in an acidic
environment (i.e., cytosol).
Both the vesiculated and the liposomal formulations of alpha-
tocopheryl succinate were found to be unstable by this inventor. When freshly
prepared the formulations were white and milky. Over 2 week storage at 5 C in
dark in a sealed glass vials, these pH neutral and aseptically prepared
formulations turned into yellow-green color with noticeable curd-like
precipitates
formed. An i.v. injection of such formulations into mice immediately caused
death.
It is believed that there have been extensive degradations of alpha-tocopheryl
succinate (oxidation) and aggregation of the vesicles and liposomes.
Hydrolysis of
aipha-tocopheryl succinate in these formulations during the storage might also
have occurred.
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To develop a therapeutically feasible alpha-tocopheryl succinate
product for human use, it is therefore desired to have a stable and
intravenously
injectable formulation for alpha-tocopheryl succinate that is free from any
deleterious ingredients such as DMSO. Furthermore, it is likely that the lack
of
such a clinically feasible formulation has impeded the clinical development of
alpha-tocopheryl succinate as an anti-cancer drug. The present invention meets
the above needs and provides additional related advantages.
BRIEF SUMMARY OF THE INVENTION
The present invention, in one aspect, provides new compositions of
alpha-tocopheryl succinate that are stable and suitable for injection. In
particular,
this invention is directed to a composition that comprises alpha-tocopheryl
succinate, an analogue or a salt thereof; at least one component selected from
the
group consisting of an oil component, phospholipid, and antioxidant; and
water;
wherein the composition is a colloidal dispersion having an average particle
size
less than about 1000 nm (e.g., less than 200 nm) in diameter, and wherein the
alpha-tocopheryl succinate, analogue or salt thereof is stable for at least 1
month
(e.g., at least 6 months) at room temperature.
In certain embodiments, the present invention provides a
pharmaceutical composition that comprises alpha-tocopheryl succinate, an
analogue or a salt thereof, an oil component, and water, wherein the
composition
is a colloidal dispersion having an average particle size less than about 1000
nm
(e.g., less than 200 nm) in diameter, and wherein the alpha-tocopheryl
succinate,
analogues or salts thereof is stable for at least 1 month (e.g., at least 6
months) at
room temperature.
In certain - embodiments, the present invention provides a
pharmaceutical composition that comprises alpha-tocopheryl succinate, an
analogue or a salt thereof, phospholipid, and water, wherein the composition
is a
colloidal dispersion having an average particle size less than about 1000 nm
(e.g.,
less than 200 nm) in diameter, and wherein the alpha-tocopheryl succinate,
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analogues or salts thereof is stable for at least 1 month (e.g., at least 6
months) at
room temperature.
In certain embodiments, the present invention provides a
pharmaceutical composition that comprises alpha-tocopheryl succinate, an
analogue or a salt thereof, an antioxidant, and water, wherein the composition
is a
colloidal dispersion having an average particle size less than about 1000 nm
(e.g.,
less than 200 nm) in diameter, and wherein the alpha-tocopheryl succinate,
analogues or salts thereof is stable for at least 1 month (e.g., at least 6
months) at
room temperature.
In certain embodiments, the present invention provides a
pharmaceutical composition that comprises alpha-tocopheryl succinate, an
analogue or a salt thereof, an oil component, phospholipid, and water, wherein
the
composition is a colloidal dispersion having an average particle size less
than
about 1000 nm (e.g., less than 200 nm) in diameter, and wherein the alpha-
tocopheryl succinate, analogues or salts thereof is stable for at least 1
month (e.g.,
at least 6 months) at room temperature.
In certain embodiments, the present invention provides a
pharmaceutical composition that comprises alpha-tocopheryl succinate, an
analogue or a salt thereof, an oil component, an antioxidant, and water,
wherein
the composition is a colloidal dispersion having an average particle size less
than
about 1000 nm (e.g., less than 200 nm) in diameter, and wherein the alpha-
tocopheryl succinate, analogues or salts thereof is stable for at least 1
month (e.g.,
at least 6 months) at room temperature.
In certain embodiments, the present invention provides a
pharmaceutical composition that comprises alpha-tocopheryl succinate, an
analogue or a salt thereof, phospholipid, an antioxidant, and water, wherein
the
composition is a colloidal dispersion having an average particle size less
than
about 1000 nm (e.g., less than 200 nm) in diameter, and wherein the alpha-
tocopheryl succinate, analogues or salts thereof is stable for at least I
month (e.g.,
at least 6 months) at room temperature.
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In certain embodiments, the present invention provides a
pharmaceutical composition that comprises alpha-tocopheryl succinate, an
analogue or a salt thereof, an oil component, phospholipid, an antioxidant,
and
water, wherein the composition is a colloidal dispersion having an average
particle
size less than about 1000 nm (e.g., less than 200 nm) in diameter, and wherein
the
alpha-tocopheryl succinate, analogues or salts thereof is stable for at least
1
month (e.g., at least 6 months) at room temperature.
In another aspect, the present invention provides a pharmaceutical
composition that comprises alpha-tocopheryl succinate, an analogue or a salt
thereof; at least one component selected from the group consisting of an oil
component, phospholipid, and an antioxidant; and a cryoprotectant; wherein the
composition is a dry solid, the alpha-tocopheryl succinate, analogues or salts
thereof in the composition is stable for at least I month (e.g., at lest 6
months) at
room temperature, and the dry solid, upon addition of water, forms a colloidal
dispersion having an average particle size less than 1000 nm (e.g., less than
200
nm) in diameter.
In certain embodiments, the present invention provides a
pharmaceutical composition that comprises alpha-tocopheryl succinate, an
analogue or a salt thereof, an oil component, and a cryoprotectant; wherein
the
composition is a dry solid, the alpha-tocopheryl succinate, analogues or salts
thereof in the composition is stable for at least 1 month (e.g., at lest 6
months) at
room temperature, and the dry solid, upon addition of water, forms a colloidal
dispersion having an average particle size less than 1000 nm (e.g., less than
200
nm) in diameter.
In certain embodiments, the present invention provides a
pharmaceutical composition that comprises alpha-tocopheryl succinate, an
analogue or a salt thereof, phospholipid, and a cryoprotectant; wherein the
composition is a dry solid, the alpha-tocopheryl succinate, analogues or salts
thereof in the composition is stable for at least 1 month (e.g., at lest 6
months) at
room temperature, and the dry solid, upon addition of water, forms a colloidal
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dispersion having an average particle size less than 1000 nm (e.g., less than
200
nm) in diameter.
In certain embodiments, the present invention provides a
pharmaceutical composition that comprises alpha-tocopheryl succinate, an
analogue or a salt thereof, an antioxidant, and a cryoprotectant; wherein the
composition is a dry solid, the alpha-tocopheryl succinate, analogues or salts
thereof in the composition is stable for at least 1 month (e.g., at lest 6
months) at
room temperature, and the dry solid, upon addition of water, forms a colloidal
dispersion having an average particle size less than 1000 nm (e.g., less than
200
nm) in diameter.
In certain embodiments, the present invention provides a
pharmaceutical composition that comprises alpha-tocopheryl succinate, an
analogue or a salt thereof, an oil component, phospholipid, and a
cryoprotectant;
wherein the composition is a dry solid, the alpha-tocopheryl succinate,
analogues
or salts thereof in the composition is stable for at least 1 month (e.g., at
lest 6
months) at room temperature, and the dry solid, upon addition of water, forms
a
colloidal dispersion having an average particle size less than 1000 nm (e.g.,
less
than 200 nm) in diameter.
In certain embodiments, the present invention provides a
pharmaceutical composition that comprises alpha-tocopheryl succinate, an
analogue or a salt thereof, phospholipid, an antioxidant, and a
cryoprotectant;
wherein the composition is a dry solid, the alpha-tocopheryl succinate,
analogues
or salts thereof in the composition is stable for at least 1 month (e.g., at
lest 6
months) at room temperature, and the dry solid, upon addition of water, forms
a
colloidal dispersion having an average particle size less than 1000 nm (e.g.,
less
than 200 nm) in diameter.
In certain embodiments, the present invention provides a
pharmaceutical composition that comprises alpha-tocopheryl succinate, an
analogue or a salt thereof, an oil component, phospholipid, an antioxidant,
and a
cryoprotectant; wherein the composition is a dry solid, the alpha-tocopheryl
succinate, analogues or salts thereof in the composition is stable for at
least 1
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month (e.g., at lest 6 months) at room temperature, and the dry solid, upon
addition of water, forms a colloidal dispersion having an average particle
size less
than 1000 nm (e.g., less than 200 nm) in diameter.
In certain embodiments, the pharmaceutical compositions are
chemically stabilized by the addition of stabilizers and/or removal of water.
For
example, the stabilizers may be antioxidants, and the removal of water may be
accomplished by freeze-drying, vacuum drying, or spray drying.
In certain embodiments, the colloidal dispersion of this invention is
physically stabilized by addition of an oil component, phospholipid and
optionally a
cryoprotectant, wherein the colloidal dispersion is a submicron-sized
suspension,
or oil-in-water emulsion.
In certain embodiments, the pharmaceutical compositions of the
invention are chemically stable for at least 1, 2, 3, 4, 5, or 6 months at
room
temperature, wherein the loss of intact alpha-tocopheryl succinate (or its
analogue
or salt) is no more than about 15% by at least 1, 2, 3, 4, 5, or 6 months. In
certain
embodiments, the loss of intact alpha-tocopheryl succinate (or its analogue or
salt)
is no more than about 10%, 7.5%, or 5%.
In certain embodiments, the pharmaceutical compositions of the
invention are physically stable for at least 1, 2, 3, 4, 5, or 6 months at
room
temperature, wherein the average size of the particles does not increase by
more
than about 100% by at least 1, 2, 3,4, 5, or 6 months. In certain embodiments,
the
average size of the particles does not increase by more than about 10%, 20%,
30%, 40%, 50%, 60%, 70%, 80%, or 90%.
In certain embodiments, the average particle size of the colloidal
dispersion of the present invention is less than about 500 nm, 400 nm, 300 nm,
250 nm, 200 nm, 150 nm, or 100 nm.
This invention also relates to a method of using the pharmaceutical
composition for treating various forms of cancer (e.g., through injections),
wherein
the active anticancer component is alpha-tocopheryl succinate, its analogues
or
salts, or the combination of alpha-tocopheryl succinate, its analogues or
salts and
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one or more other anticancer agents, including a taxoid analog (e.g.,
paclitaxel and
docetaxel).
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides stable alpha-tocopheryl succinate
colloidal dispersions or dry solid that may be re-hydrated into colloidal
dispersions.
The alpha-tocopheryl succinate colloidal dispersions may comprise alpha-
tocopheryl succinate, analogues or salts thereof, and optionally in
combination with
another anticancer agent; at least one component selected from the group
consisting of an oil component, phospholipid, and an antioxidant; and water.
The
alpha-tocopheryl succinate dry solid may comprise alpha-tocopheryl succinate,
analogues or salts thereof, or optionally in combination with another
anticancer
agent; and at least one component selected from the group consisting of an oil
component, phospholipid(s), and an antioxidant; and a cryoprotectant.
In one aspect, the invention is directed to the use of alpha-tocopheryl
succinate (or its analogues or salts) as an anticancer therapeutic agent in an
oil-in-
water emulsion, wherein alpha-tocopheryl succinate constitutes chiefly the oil
phase of the emulsion. Alpha-tocopheryl succinate is not a typical lipid oil:
It has a
higher polarity than most lipid oils, particularly triglycerides, and is not
saponifiable.
The hydrophilicity of alpha-tocopheryl succinate is highly pH dependent. At a
low
pH, generally below pH 5, the end carboxylic acid group of the succinic acid
of
alpha-tocopheryl succinate is protonated, and alpha-tocopheryl succinate
remains
a highly hydrophobic solid and does not disperse in water well. At a pH above
5,
alpha-tocopheryl succinate is more hydrophilic as the end carboxylic acid
group of
the succinic acid becomes deprotonated. The deprotonated alpha-tocopheryl
succinate is not soluble in water, but behaves like a surfactant of low
(Hydrophile-
Liphophile Balance) HLB value in water. Thus, upon agitation, the deprotonated
alpha-tocopheryl succinate forms an oil-in-water emulsion wherein the oil
phase is
chiefly alpha-tocopheryl succinate. However, an emulsion formed by alpha-
tocopheryl succinate alone (as described in Cancer Lett. 192: 19-24, 2003)
appeared to have insufficient stability due to the chemical degradation of
alpha-
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tocopheryl succinate and aggregation of the oil droplets. The present
invention
provides a new emulsion of alpha-tocopheryl succinate with enhanced stability
by
the addition of at least one component selected from the group consisting of
an oil
component, phospholipid, and antioxidant, wherein the alpha-tocopheryl
succinate
may be in either the deprotonated or protonated form, or a mixture thereof.
In another aspect, the invention is directed to the use of alpha-
tocopheryl succinate (or its analogues or salts) as the anticancer therapeutic
agent
in a solid-in-water suspension, wherein alpha-tocopheryl succinate constitutes
chiefly the solid phase of the suspension. In its protonated form, alpha-
tocopheryl
succinate remains as a solid form and does not form a stable suspension. This
invention provides a new alpha-tocopheryl succinate suspension with enhanced
stability by the addition of at least one component selected from the group
consisting of an oil component, phospholipid, and antioxidant.
In another aspect, the invention comprises an oil-in-solid colloidal
dispersion containing alpha-tocopheryl succinate (or its analogues or salts)
in the
oil droplets, wherein the solid continuous phase is chiefly a cryoprotectant
and
substantially free of water. In certain embodiments, the water content of an
oil-in-
solid colloidal dispersion is about, less than about, 10%, 9%, 8%, 7%, 6%, 5%,
4%, 3%, 2% or 1% of the total weight. Upon addition of water or an aqueous
medium, the oil-in-solid colloidal dispersion forms an oil-in-water emulsion
with the
average oil droplet size less than about 5 micron, in certain embodiments,
about or
less than about 500 nm, 400 nm, 300 nm, 250 nm, 200 nm, 150 nm, or 100 nm.
In another aspect, the invention provides a solid-in-solid colloidal
dispersion containing alpha-tocopheryl succinate (or its analogues or salts)
in the
solid particles, wherein the solid continuous phase is chiefly a
cryoprotectant and
substantially free of water. In certain embodiments, the water content of the
solid-
in-solid colloidal dispersion is less than about 10%, 9%, 8%, 7%, 6%, 5%, 4%,
3%,
2% or 1% of the total weight. Upon addition of water or an aqueous medium, the
said solid-in-solid colloidal dispersion forms a solid-in-water suspension
with the
average particle size less than 5 micron, in certain embodiments, less than
about
500 nm, 400 nm, 300 nm, 250 nm, 200 nm, 150 nm, or 100 nm. In certain
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embodiments, the concentration of alpha-tocopheryl succinate (or its analogue
or
salt) in the solid-in-solid colloidal dispersion may be about 1% to about 30%,
about
2% to about 20%, or about 5% to about 15%, by weight. In certain embodiments,
the concentration of the dispersed solid component in the solid-in-solid
colloidal
dispersion may be about 1% to about 20%, about 2% to 15%, or about 3% to 5%,
by weight.
"Concentration by weight," as used herein, refers to the ratio (in
percentage) of the weight of a component (e.g., alpha-tocopheryl succinate) of
a
composition (e.g., a colloidal suspension) to the total weight of the
composition, if
not otherwise noted.
The colloidal dispersions of the invention for intravenous injection
have an average particle size of about 10 to about 1000 nm. In certain
embodiments, the average particle size is about 10 to about 500 nm, about 10
nm
to about 200 nm, or about 50 to about 150 nm. In certain embodiments, the
average particle size is about, or less than about 50 nm, 75 nm, 100 nm, 125
nm,
150 nm, 175 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900
nm, or 1000 nm.
Alpha tocopherol is ( )-(2RS,4' RS,8' RS)-2, 5, 7, 8-tetramethyl-2-(4',
8', 12'-trimethyltridecyl)-6-chromanol. Its nonproprietary names include Alpha
Tocopherol by British Pharmacopoeia, a-Tocopherolum by PhEur, and Vitamin E
by the United State Pharmacopoeia. Its CAS Registry Number is 10191-41-0. Its
empirical formuia is C29H5002 and molecular weight is 430.69. The structures
of
alpha tocopherol and its homologues are shown below.
R,
HO
/ I CH
3
R ' O
z CH3
3
CH3 CH3 CH
R3
Rl, R2, and R3 may be H or CH3.
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Homologues Ri R2 R3
Alpha-tocopherol CH3 CH3 CH3
Beta-tocopherol CH3 H CH3
Gamma-tocopherol H CH3 CH3
Delta-tocopherol H H CH3
The naturally occurring form is known as d-alpha tocopherol or
simply alpha tocopherol. Alpha tocopherol has three chrial centers giving rise
to
eight isomers. The d- isomeric form represents the (2R, 4'R, 8'R)-alpha-
tocopherol
or sometimes, RRR-alpha-tocopherol.
"Alpha-tocopheryl succinate" refers to a hemi-ester of succinic acid
with alpha tocopherol, such as d-alpha-tocopheryl acid succinate (C33H5405, MW
530.8, CAS number 4345-03-3). The chemical structures of alpha-tocopheryl
succinate and its analogues are shown below.
R1
RO
CH3
R2 CH3
CH3 CH
y 3 CH3
R3
Rl, R2, R3=H or CH3
R = -OOC-(CH2)n-COOH
Analogues n Dicarboxylic acids
Alpha-tocopheryl oxalate 0 Oxalic acid
Alpha-tocopheryl malonate I Malonic acid
Alpha-tocopheryl succinate 2 Succinic acid
Alpha-tocopheryl glutarate 3 Glutaric acid
Alpha-tocopheryl adipate 4 Adipic acid
Alpha-tocopheryl pimelate 5 Pimelic acid
Alpha-tocophe I suberate 6 Suberic acid
Alpha-tocopheryl azelate 7 Azelaic acid
"Alpha-tocopheryl succinate," in certain embodiments, may include
isomers such as dl-alpha-tocopheryl acid succinate (CAS number 17407-37-3). It
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may, in certain embodiments, include beta tocopheryl acid succinate, delta
tocopheryl acid succinate, gamma tocopheryl acid succinate, or isomers
thereof.
The term of "alpha-tocopheryl succinate analogues" used in this
invention refers to hemi-esters of short-chain dicarboxylic acids with alpha
tocopherol, wherein the dicarboxylic acids have the general type formula:
HOOC-(CH2)n-COOH
Short-chain dicarboxylic acids include oxalic acid (n=0), malonic acid
(n=1), succinic acid (n=2), glutaric acid (n=3), adipic acid (n=4), pimelic
acid (n=5),
suberic acid (n=6), and azelaic acid (n=7) acids.
Alpha-tocopheryl succinate analogues useful in the present invention
generally have anticancer activity (i.e., the ability to inhibit cancer growth
or cause
cancer cell death). In certain embodiments, the anticancer activity of an
alpha-
tocopheryl succinate analogue is statistically higher than that of alpha-
tocopheryl
succinate.
The term of "alpha-tocopheryl succinate salts" of this invention refers
to an ionic ion salt of pharmaceutically acceptable inorganic counter ions
(e.g.,
sodium, potassium, lithium, calcium, magnesium, and aluminum) and organic
counter ions (e.g., amines, lysine, and arginine). Alpha-tocopheryl succinate
salts
useful in the present invention generally have anticancer activity.
Alpha-tocophery succinate, a hemi-ester of alpha tocopherol,
structurally and functionally differs from the other three common types of
vitamin E
derivatives: tocopherol, tocopherol monoester (e.g., acetate), and tocopherol
polyetheleneglycol succinate (also referred to as tocopherol PEG ester or
vitamin
E TPGS). The hemi-esters contain an open (non-esterified) carboxylic acid
group
and are ionizable, whereas all the others are non-ionizable. Thus, when
included
as a component in a formulation, the hemi-esters function very different from
the
monoesters or the parent tocopherol. While a monoester or the parent
tocopherol
is lipophilic and oil soluble, the hemi-esters are not soluble in either water
or oil
and are not good solvent or solubilizer for either hydrophilic or hydrophobic
drugs.
When the open (non-esterified) carboxylic acid group on a hemiester is ionized
at
a pH about 7 or above, the hemi-esters behave like a surfactant of low HLB
value
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(i.e. water insoluble type) and yet they are not good surfactants like vitamin
E
TPGS. For example, unlike vitamin E TPGS, tocopherol succinate is incapable of
solubilizing a lipophilic drug by forming micelles in water, or emulsifying an
vegetable oil in water to form a stable oil-in-water emulsion. By appearance,
tocopherol succinate is a crystalline solid, whereas tocopherol and tocopherol
acetate are oily liquid, and vitamin E TPGS is a water-soluble wax-like
material.
In certain embodiments, the formulations of the present invention
does not comprise both alpha-tocopherol and vitamin E TPGS, or either of them.
In certain embodiments, the concentration of alpha-tocopheryl
succinate (or its analogue or salt) in a colloidal suspension of the present
invention
is about 1% to 20% by weight. In certain embodiments, the concentration is
about
2% to 15%, or 5% to 10% by weight. In certain embodiments, the concentration
is
about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11 %, 12%, 13%, 14%, 15%,
16%, 17%, 18%, 19%, or 20% by weight.
The term "oil" is used herein in a general sense to identify
hydrocarbon derivatives, carbohydrate derivatives, or similar organic
compounds
that are liquid at body temperatures, e.g., about 37 C, and are
pharmacologically
acceptable in injectable formulations. It includes glycerides or non-
glycerides.
The term "oil component" refers to an oil, or a combination of multiple
oils in a colloidal dispersion or a dry solid, which may be re-hydrated into a
colloidal dispersion. This term does not include alpha-tocopheryl succinate,
its
analogues, or the salts of alpha-tocopheryl succinate or its analogues.
In certain embodiments, the oil component of a colloidal dispersion or
dry solid of the present invention comprises a monoglyceride, a diglyceride, a
triglyceride, or a mixture thereof. In certain embodiments, the oil component
comprises an ester formed between one or more fatty acids and an alcohol other
than glycerol.
"Vegetable oil" refers to oiI derived from plant seeds or nuts.
Exemplary vegetable oils include, but are not limited to, almond oil, borage
oil,
black currant seed oil, corn oil, safflower oil, soybean oil, sesame oil,
cottonseed
oil, peanut oil, olive oil, rapeseed oil, coconut oil, palm oil, canola oil,
etc.
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Vegetable oils are typically "long-chain triglycerides," formed when
three fatty acids (usually about 14 to about 22 carbons in length, with
unsaturated
bonds in varying numbers and locations, depending on the source of the oil)
form
ester bonds with the three hydroxyl groups on glycerol. In certain
embodiments,
vegetable oils of highly purified grade (also called "super refined") are
generally
used to ensure safety and stability of oil-in-water emulsions. In certain
embodiments, hydrogenated vegetable oils, which are produced by controlled
hydrogenation of the vegetable oil, may be used in the present invention.
"Medium chain triglycerides" (MCT's) is another class of triglyceride
oil that can be either naturally derived or synthetic. MCT's are made from
fatty
acids that are usually about 8 to about 12 carbons in length. Like vegetable
oils,
MCT's have been used extensively in emulsions designed for injection as a
source
of calories, for patients requiring parenteral nutrition. Such oil is
commercially
available as Miglyol 812 from SASOL GmbH, Germany, CRODAMOL GTCC-PN
from Croda Inc. of Parsippany, New Jersey, or Neobees M-5 oil from PVO
International, Inc., of Boonton, New Jersey. Other low-melting medium chain
oils
may also be used in the present invention.
"Animal fat" refers to oil derived from an animal source. It also
comprises triglycerides, but the lengths of, and unsaturated bonds in, the
three
fatty acid chains vary, compared to vegetable oils. Animal fats from sources
that
are solid at room temperature (such as tallow, lard, etc.) can be processed to
render them liquid if desired. Other types of animal fats that are inherently
liquid at
room temperature include various fish oils, etc.
In certain embodiments, the combinations of vegetable oil and MCT
oil are used in the present invention. Such combinations generally have long
record of safe use in combination in injectable emulsions and provide the
superior
stability for the colloidal dispersions or dry solid of this invention. The
specific type
of vegetable oil used (i.e., soy bean oil, corn oil, or safflower oii, etc.)
is not critical,
so long as it is safe, well tolerated, pharmaceutically acceptable, and
chemically
stable and provides dispersion droplets having a desired size range.
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The content of the total oil component in the colloidal suspensions of
this invention may be within a range of about 1% to about 20%, by weight. In
certain embodiments, the total concentration of the oil component is within a
range
of about 2% to about 10%, or about 3% to about 5%. In certain embodiments, the
total concentration of the oil component is about, or at most about 1%, 2%,
3%,
4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 15%, 17%, or 20% by weight. In certain
embodiments, the colloidal suspensions comprise oil in an amount that does not
result in hyperlipodemia when administered to a subject.
In certain embodiments, the vegetable oil to MCT oil ratio in a
colloidal suspension is within a range of about 5:1 to about 1:5, by weight.
In
certain embodiments, the ratio of the vegetable oil to MCT oil is within a
range of
about 2:1 to about 1:2. In certain embodiments, the ratio of the vegetable oil
to
MCT oiI is about 5:1, 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:4 or 1:5.
The non-glycerides referred in this invention are chiefly cholesterol
and derivatives thereof.
In certain embodiments, the oil component of a formulation of the
present invention comprises soybean oil and cholesterol.
In certain embodiments, the ratio of alpha-tocopheryl succinate (or its
analogue or salt) to the oil component (e.g., triglyceride or cholesterol) in
the
colloidal dispersion of this invention is from about 5:1, 4:1, 3:1, 2:1, 1:1,
1:2, 1:3,
1:4, or 1:5.
A "phospholipid" refers to a triester of glycerol with two fatty acids
and one phosphate ion. Exemplary phospholipids useful in the present invention
include, but are not limited to, phosphatidyl chlorine, lecithin (a mixture of
choline
ester of phosphorylated diacylglyceride), phosphatidylethanolamine,
phosphatidylglycerol, phosphatidic acid with about 4 to about 22 carbon atoms,
and more generally from about 10 to about 18 carbon atoms and varying degrees
of saturation. The phospholipid component of the drug delivery composition can
be either a single phospholipid or a mixture of several phospholipids. The
phospholipids should be acceptable for the chosen route of administration.
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The phospholipids useful in the present invention can be of natural
origin. Naturally occurring phospholipids include soy lecithin, egg lecithin,
hydrogenated soy lecithin, hydrogenated egg lecithin, sphingosine,
gangliosides,
and phytosphingosine and combinations thereof.
Naturally occurring lecithin is a mixture of the diglycerides of stearic,
paimitic, and oleic acids, linked to the choline ester of phosphoric acid,
commonly
called phosphatidylcholine, and can be obtained from a variety of sources such
as
eggs and soya beans. Soy lecithin and egg lecithin (including hydrogenated
versions of these compounds) have a long history of safety, possess combined
emulsification and solubilization properties, and tend to be broken down into
innocuous substances more rapidly than most synthetic surfactants.
Commercially
available soya phospholipids are the Centrophase and Centrolex products
marketed and sold by Central Soya, Phospholipon from Phospholipid GmbH,
Germany, Lipoid by Lipoid GmbH, Germany, and EPIKURON by Degussa.
Hydrogenated lecithin is the product of controlled hydrogenation of
lecithin. It may also be used in the present invention.
According to the United State Pharmacopoeia (USP), lecithin is a
non-proprietary name describing a complex mixture of acetone-insoluble
phospholipids, which consists chiefly of phosphotidyicholine,
phosphotidylethanolamine, phosphotidyiserine and phosphotidylinositol,
combined
with various amounts of other substances such as triglycerides, fatty acids,
and
carbohydrates.
Pharmaceutically, lecithins are mainly used as dispersing,
emulsifying, and stabilizing agents and are included in intramuscular and
intravenous injections, parenteral nutritional formulations and topical
products.
Lecithin is also listed in the FDA Inactive Ingredients Guide for use in
inhalations,
IM and IV injections, oral capsules, suspensions and tablets, rectal, topical,
and
vaginal preparations.
Phospholipids can also be synthesized and the common synthetic
phospholipids are listed below:
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Diacylglycerols
1,2-Dilauroyl-sn-glycerol (DLG)
1,2-Dimyristoyl-sn-glycerol (DMG)
1,2-Dipaimitoyl-sn-glycerol (DPG)
1,2-Distearoyl-sn-glycerol (DSG)
Phosphatidic Acids
1,2-Dimyristoyl- sn-glycero-3-phosphatidic acid, sodium salt (DMPA,Na)
1,2-Dipaimitoyl- sn-glycero-3-phosphatidic acid, sodium salt (DPPA,Na)
1,2-Distearoyl- sn-glycero-3-phosphatidic acid, sodium salt (DSPA,Na)
Phosphocholines
1,2-Dilauroyl-sn-glycero-3-phosphocholine (DLPC)
1,2-Dimyristoyl-sn-glycero-3-phosphocholine (DMPC)
1,2-Dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)
1,2-Distearoyl-sn-glycero-3-phosphocholine (DSPC)
Phosphoethanolamines
1,2-Dilauroyl-sn-glycero-3-phosphoethanolamine (DLPE)
1,2-Dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE)
1,2-Dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE)
1,2-Distearoyl-sn-glycero-3-phosphoethanolamine (DSPE)
Phosphoglycerols
1,2-Dilauroyl-sn-glycero-3-phosphoglycerol, sodium salt (DLPG)
1,2-Dimyristoyl-sn-glycero-3-phosphoglycerol, sodium salt (DMPG)
1,2-Dimyristoyl-sn-glycero-3-phospho- sn-1-glycerol, ammonium salt (DMP-sn-
1-G, N H4)
1,2-Dipaimitoyl- sn-glycero-3-phosphoglycerol, sodium salt (DPPG,Na)
1,2-Distearoyl- sn-glycero-3-phosphoglycerol, sodium salt (DSPG,Na)
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1,2-Distearoyl- sn-glycero-3-phospho- sn-1-glycerol, sodium salt (DSP-sn-
1G,Na)
Phosphoserines
1,2-Dipalmitoyl- sn-glycero-3-phospho-L-serine, sodium salt (DPPS,Na)
Mixed Chain Phospholipids
1-Paimitoyl-2-oleoyl- sn-glycero-3-phosphocholine (POPC)
1-Palmitoyl-2-oleoyl- sn-glycero-3-phosphoglycerol, sodium salt (POPG,Na)
1-Palmitoyl-2-oleoyl- sn-glycero-3-phosphoglycerol, ammonium salt
(POPG,NH4)
Lysophospholipids
1 -Palm itoyl-2-lyso- sn-glycero-3-phosphocholine (P-lyso-PC)
1-Stearoyl-2-Iyso- sn-glycero-3-phosphocholine (S-lyso-PC)
Pegylated Phospholipids
N-(Carbonyl-methoxypolyethyleneglycoi 2000)- MPEG-2000-DPPE
1,2-dipalmitoyl- sn-glycero-3-phosphoethanolamine, sodium salt
N-(Carbonyl-methoxypolyethyleneglycol 5000)- MPEG-5000-DSPE
1,2-distearoyl- sn-glycero-3-phosphoethanolamine, sodium salt
N-(Carbonyl-methoxypolyethyleneglycol 5000)- MPEG-5000-DPPE
1,2-dipaimitoyl- sn-glycero-3-phosphoethanolamine, sodium salt
N-(Carbonyl-methoxypolyethyleneglycol 750)- MPEG-750-DSPE
1,2-distearoyl- sn-glycero-3-phosphoethanolamine, sodium salt
N-(Carbonyl-methoxypolyethyleneglycol 2000)- MPEG-2000-DSPE
1,2-distearoyl- sn-glycero-3-phosphoethanolamine, sodium salt
The amount of phospholipids, by weight, in the colloidal suspensions
or dry solid of this invention may be within a range of about 0.5% to about
10%. In
certain embodiments, the amount of phospholipids, by weight, may be within a
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range of about 1% to about 5%, or about 2% to about 3%. In certain
embodiments, the amount of phospholipids is about 0.5%, 1%, 2%, 3%, 4%, 5%,
6%, 7%, 8%, 9% or 10%.
In certain embodiments, the ratio of alpha-tocopheryl succinate to
phospholipid in the colloidal dispersion of this invention is from about 5:1
to about
1:5 (w/w). In certain embodiments, the ratio is about 5:1, 4:1, 3:1, 2:1, 1:1,
1:2,
1:3, 1:4, or 1:5.
A "colloidal dispersion" refers to a system in which particles of
colloidal size of any nature (e.g., solid, liquid or gas) are dispersed in a
continuous
phase of a different composition (or state).
The term "colloidal" refers to a state of subdivision, implying that the
molecules or polymolecular particles dispersed in a medium have at least, in
one
direction, a dimension roughly between 1 nm and 1 mm, or that in a given
system,
discontinuities are found at distances of that order (1972, 31, 605, IUPAC
Compendium of Chemical Terminology, 2nd Edition,1997).
In certain embodiments, a colloidal dispersion of this invention is an
emulsion, i.e., a colloidal dispersion of a water-immiscible liquid dispersed
in an
aqueous medium ("oil-in-water type colloidal dispersion"). The water-
immiscible
liquid is in a form of oil droplets comprising alpha-tocopheryl succinate and
optionally another therapeutic agent and/or other water insoluble components,
whose diameter are generally between about 0.1 and about 3.0 microns. The
emulsion is typically optically opaque unless the dispersed and continuous
phases
are refractive index matched. Such systems possess a finite stability,
generally
defined by the application or relevant reference system, which may be enhanced
by the addition at least one component selected from a group consisting of an
oil
component, phospholipid, and antioxidant.
In certain other embodiments, a colloidal dispersion of this invention
is a suspension in an aqueous medium ("solid-in-water type colloidal
dispersion").
The suspension of this invention is a colloidal dispersion of a water-
insoluble solid
phase comprising alpha-tocopheryl succinate and optionally another therapeutic
agent and/or other water insoluble components in the form of small particles
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whose diameters are generally between 0.1 and 3.0 microns. The suspension is
typically optically opaque unless the dispersed and continuous phases are
refractive index matched. Such systems possess a finite stability, generally
defined
by the application or relevant reference system, which may be enhanced by the
addition at least one component selected from a group consisting of an oil
component, phospholipid, and antioxidant.
In certain other embodiments, a colloidal dispersion of this invention
is a dispersion of oil droplets in a solid continuous phase (oil-in-solid type
colloidal
dispersion). The oil droplets comprise alpha-tocopheryl succinate and
optionally
another therapeutic agent and/or other water insoluble components. The
continuous phase is a solid matrix comprising primarily a cryo-protectant.
This
colloidal dispersions may be formed by freeze-drying or spray drying an oil-in-
water type colloidal dispersion. Such oil-in-solid systems possess an enhanced
stability compared to the oil-in-water colloidal dispersion, generally due to
the
removal of water from the continuous phase.
In certain other embodiments, a colloidal dispersion of this invention
is a dispersion of solid particles in a solid continuous phase ("solid-in-
solid type
colloidal dispersion"). The solid particles comprise alpha-tocopheryl
suceinate
and optionally another therapeutic agent and/or other water insoluble
components.
The continuous phase is a solid matrix comprising primarily a cryo-protectant.
This
colloidal dispersion may be formed by freeze-drying or spray drying a solid-in-
solid
type colloidal dispersion. Such solid-in-solid systems possess an enhanced
stability compared to the solid-in-water colloidal dispersion, generally due
to the
removal of water from the continuous phase.
"Aqueous medium" or "aqueous phase" refers to a water-containing
liquid which can contain pharmaceutically acceptable additives, such as
acidifying,
alkalizing, buffering, chelating, complexing and solubilizing agents,
antioxidants
and antimicrobial preservatives, suspending and/or viscosity modifying agents,
tonicity modifying agent, cryo-protectant, and other biocompatible materials
or
therapeutic agents. In certain embodiments, such additives assist in
stabilizing the
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colloidal dispersion or in rendering the formulations of the present invention
biocompatible.
The aqueous phase generally has an osmolality of approximately
300 mOsm and may include potassium or sodium chloride, trahalose, sucrose,
sorbitol, glycerol, mannitol, polyethylene glycol, propylene glycol, albumin,
amino
acid and mixtures thereof. In certain embodiments, a tonicity of at least 250
mOsm
is achieved with an agent that also increases viscosity, such as sorbitol or
sucrose.
"Antioxidants" used in this invention refer to primarily metal ion
chelator and/or reducing agents that are safe to use in an injectable product.
A
metal ion chelator works as an antioxidant by binding to metal ions and
thereby
reduces the catalytic effect of metal ion on the oxidation reaction of alpha-
tocopheryl succinate. Metal chelators that are useful in this invention may
include
EDTA, glycine and citric acid or salts thereof.
In certain embodiments, the concentration of disodium edetate in the
colloidal dispersion of this invention can be from about 0.0001 % to about 1%
w/v.
In certain embodiments, the concentration is from about 0.001% to about 0.1%
w/v, or from about 0.001 % to about 0.005% w/v.
The reducing agents exhibit their antioxidant effect by reacting with
oxidizing agents in competition with alpha-tocopheryi succinate or by
converting
oxidized alpha-tocopheryl succinate back to the original alpha-tocopheryl
succinate
in the reduced form. The reducing agents useful in this invention include, but
are
not limited to, ascorbic acid or salts thereof, ascorbyl palmitate, sodium
metabisulfite, propyl gallate, butylated hydroxyanisole, butylated
hydroxytoluene,
tocopherol, amino acids or salts thereof, citric acid or salts thereof,
reducing
sugars, or mixtures thereof.
A "cryoprotectant" of this invention refers to a safe and biocompatible
agent that protects the oil-in-water or solid-in-water colloidal dispersion
during
freezing or freeze-drying by maintaining the discrete and sub-micron size
droplets
or particles in the aqueous surrounding. The cryoprotectants of this invention
also
function as the main component of the continuous phase of the oil-in-solid or
solid-
in-solid colloidal dispersion. The cryoprotectants useful for this invention
include,
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but are not limited to, monosaccharide, disaccharide, polysaccharide,
propylene
glycol, polyethylene glycol, glycerol, poly-ol, dextrin, cyclodextrin, starch,
cellulose
and cellulose derivative, protein, peptide, amino acid, sodium chloride,
polyvinypyrrolidone, or mixtures thereof. For instance, in certain
embodiments, the
cryoprotectant is mannitol, sorbitol, xylitol, lactose, fructose, xylose,
sucrose,
trahalose, mannose, maltose, dextrose, dexstrane, or a mixture thereof. In
certain
embodiments, the cryoprotectant is sucrose, a combination of sucrose and
mannitol, or a combination of sucrose and trehalose. In certain embodiments,
the
formulations of the present invention do not comprise acacia.
In certain embodiments, the concentration of cryoprotectants in the
oil-in-solid or solid-in-solid formulations of the present invention may be
about 30%
to 70% by weight. In certain embodiments, the concentration of sucrose may be
about 40% to 60% by weight.
The concentration of cryoprotectants in the oil-in-water or solid-in-
water colloidal dispersion of this invention may be from about 1% to about 30%
w/v. In certain embodiments, the concentration is from about 3% to about 15%
w/v
or from about 5% to 10% w/v.
"Biocompatible" refers to the capability of performing functions withiri
or upon a living organism in an acceptable manner, i.e., without undue
toxicity or
physiological or pharmacological effects.
In certain embodiments, the present compositions are both
chemically and physically stable. A composition is "chemically stable" if less
than
about 20% alpha-tocopheryl succinate in the composition is chemically degraded
after storage under appropriate conditions for a defined period of time (e.g.,
a
month). In certain embodiments, the concentration of the intact alpha-
tocopheryl
succinate (or its analogue or salt) in the composition is reduced by less than
about
5%, 10%, 15% or 20% under appropriate storage conditions (e.g., at -20 C, 2-8
C,
or room temperature) for at least 1, 2, 3, 4, 5, 6, 9, 12, 15, 18, or 24
months.
Chemical degradation of alpha-tocopheryl succinate (or its analogues
or salts) includes mainly hydrolysis of the succinate ester bond and oxidation
of the
tocopherol moiety. Hydrolysis of the succinate ester bond leads to the
formation
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of succinic acid and tocopherol, each of which is inefficacious against cancer
and
is prone to a fast oxidation. The rate of hydrolysis of alpha-tocopheryl
succinate is
pH-dependent. The removal of water in the continuous phase by freeze-drying,
spray-drying, or other drying means essentially stops the hydrolytic
degradation.
Another degradation route of alpha-tocopheryl succinate (or its
analogues or salts) is oxidation. Tocopherols are slowly oxidized by
atomospheric
oxygen and rapidly by metal ions such as ferric and silver salts. Oxidation
products
include tocopheroxide, tocopherylquinone and tocopheryihydroquinone, or dimers
and trimers thereof. Tocopherol esters such as alpha-tocopheryl succinate are
more stable to oxidation than free tocopherols. Oxidation may be prevented or
reduced by the use of an antioxidant.
A composition (e.g., a colloidal suspension or a dry solid) is
"physically stable" if it may be stored under appropriate conditions for a
defined
period of time (e.g., I month) without increase in its average particle size
by more
than 100%, or evidence of phase separation, creaming, or particle aggregation.
In
certain embodiments, the average size of particles of a composition of the
present
invention does not increase by more than about 10%, 20%, 25%, 30%, 40%, 50%,
75%, or 100% under appropriate storage conditions (e.g., at-20 C, 2-8 C, or
room
temperature) for at least 1, 2, 3, 4, 5, 6, 9, 12, 15, 18, or 24 months.
In certain embodiments, a colloidal dispersion composition of alpha-
tocopheryl succinate is capable of retaining no less than 90% of the intact
alpha-
tocopheryl succinate (or its analogue or salt) and is substantially free from
aggregates of greater than 5-micron in diameter for at least 6 months at room
temperature. In certain embodiments, a colloidal dispersion composition of
alpha-
tocopheryl succinate is capable of retaining no less than 92%, 94%, 95%, 96%,
97%, 98% or 99% of the intact alpha-tocopheryl succinate (or its analogue or
salt)
and is substantially free from aggregates of greater than 2-micron in diameter
for
at least 6 months at room temperature.
Unless noted otherwise, a pharmaceutical composition is "stable" if
the pharmaceutical composition is both chemically and physically stable for a
defined period of time.
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"Room temperature" refers to temperature ranging from about 20 C
to about 25 C.
"Therapeutic agent" refers to any compound natural or synthetic that
has therapeutic effects on a mammal (including human). Therapeutic agents
include anticancer agents and may be used in addition to the alpha-tocopheryl
succinate or its analogue or salt in the same formulation.
"Chemotherapeutic agents" or "anticancer agents" refer to any
natural or synthetic molecules that are effective against one or more forms of
cancer (e.g., breast, ovarian, and lung cancer). In certain embodiments, the
chemotherapeutic agents are slightly or completely lipophilic (i.e., water
insoluble),
or can be modified to be lipophilic. Chemotherapeutic agents include molecules
that are cytotoxic (anti-cancer agents), that stimulate the immune system
(immune
stimulators), and that modulate or inhibit angiogenesis.
Chemotherapeutics include, but are not limited to, alkylating agents,
antimetabolites, taxanes, cytotoxics, cytoprotectant adjuvants, LHRH
analogues,
platinum agents, anti-estrognes, anti-androgens, hormonals, aromatase
inhibitors,
cell cycle controlling agents, apoptosis agents, topoisomerase inhibitors,
angiogenesis inhibitors, immunotherapy agents, monoclonal antibodies,
retinoid,
kinase inhibitors and signal transduction inhibitors.
In certain embodiments, the chemotherapeutic is selected from
paclitaxel, docetaxel and reiated molecules collectively termed taxoids,
taxines or
taxanes.
In certain embodiments, the chemotherapeutic is selected from
podophyllotoxins and their derivatives and analogues.
In certain embodiments, chemotherapeutics useful in this invention
are camptothecins.
In certain other embodiments, chemotherapeutics useful in this
invention are the Iipophilic anthracyclines.
In certain other embodiments, chemotherapeutics useful in this
invention are compounds that are lipophilic or can be made lipophilic by
molecular
chemosynthetic modifications well known to those skilled in the art, for
example, by
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combinatorial chemistry and by molecular modeling. Such chemotherapeutics
include: Amonafide, Illudin S, 6-hydroxymethylacylfulvene Bryostatin 1, 26-
succinylbryostatin 1, Palmitoyl Rhizoxin, DUP 941, Mitomycin B, Mitomycin C,
Penclomedine, interferon alpha.2b, angiogenesis inhibitor compounds (e.g.,
cisplatin hydrophobic complexes such as 2-hydrazino-4,5-dihydro-1H-imidazole
with platinum chloride and 5-hydrazino-3,4-dihydro-2H-pyrrole with platinum
chloride), vitamin A and its derivatives.
Other chemotherpeutics useful in the invention include: 1,3-bis(2-
chloroethyl)-1-nitrosurea ("carmustine" or "BCNU"), 5-fluorouracil,
doxorubicin
("adriamycin"), epirubicin, aciarubicin, Bisantrene (bis(2-imidazolen-2-
ylhydrazone)-9, 10-anthracenedicarboxaldehyde, mitoxantrone, methotrexate,
edatrexate, muramyl tripeptide, muramyl dipeptide, lipopolysaccharides, 9-b-d-
arabinofairanosyladenine ("vidarabine") and its 2-fluoro derivative,
gemcitabine,
resveratrol, retinoic acid and retinol, carotenoids, and tamoxifen.
Other chemotherapeutics useful in this invention include:
Decarbazine, Lonidamine, Piroxantrone, Anthrapyrazoles, Etoposide,
Camptothecin, 9-aminocamptothecin, 9-nitrocamptothecin, camptothecin-11
("Irinotecan"), Topotecan, Bleomycin, the Vinca alkaloids and their analogs
[Vincristine, Vinorelbine, Vindesine, Vintripol, Vinxaltine, Ancitabine], 6-
aminochrysene, and vinorelbine.
Other chemotherapeutics useful in the present invention are
mimetics of taxol, eleutherobins, sarcodictyins, discodermolides and
epothiolones.
In certain embodiments, the presence of an anti-cancer agent other
than alpha-tocopheryl succinate or its analogue or salt in the pharmaceutical
composition of the present invention results in additive or synergistic
anticancer
activities. In certain other embodiments, the concentration of alpha-
tocopheryl
succinate or its analogue or salt in the pharmaceutical compositions of the
present
invention is relatively low (e.g., less than about 3%, 2%, or 1% by weight) so
that
alpha-tocopheryl succinate or its analogue or salt does not contribute
significantly
to the anticancer activities of the pharmaceutical compositions. In such
embodiments, alpha-tocopheryl succinate or its analogue or salt, however,
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stabilizes compositions (e.g., oil-in-water emulsions, solid-in-water
suspensions,
oil-in-solid dispersions, and solid-in-solid dispersions) that comprise
another
anticancer agent (e.g., docetaxel or paclitaxel) and thus allow for higher
loading of
the other anticancer agent in, and higher anticancer activities of, such
compositions. In certain embodiments, the present invention provides a
colloidal
dispersion comprises about 1% to about 20% (e.g., about 5% to about 15%) by
weight alpha-tocopheryl succinate, an analogue or salt thereof; about 1% to
about
20% (e.g., 3% to 5%) by weight an oil component; and optionally 0.005%-0.1 %
by
weigh edetic acid sodium salt in an aqueous medium having a pH at between
about 6 and about 8; and optionally an osmotic pressure modifier; wherein the
colloidal dispersion has an average particle diameter less than about 200 nm
(e.g.,
less than about 150 nm).
An exemplary colloidal dispersion of the present invention may
comprise about about 5% to about 15% by weight alpha-tocopheryl succinate, an
analogue or sait thereof; 3% to 5% by weight an oil component; and optionally
0.005%-0.1 % by weigh edetic acid sodium salt in an aqueous medium having a pH
at between about 6 and about 8; and optionally an osmotic pressure modifier;
wherein the colloidal dispersion has an average particle diameter less than
about
about 150 nm.
In centain embodiments, the present invention a dry solid that
comprises about 1% to about 30% (e.g., about 5% to about 15%) by weight alpha-
tocopheryl succinate, an analogue or salt thereof; about 1% to about 20%
(e.g.,
about 3% to about 5%) by weight an oil component; about 10% to about 80% by
weight cryoprotectant (e.g., sucrose); and optionally about 0.005% to about 1%
by
weigh edetic acid sodium salt; wherein the dry solid, upon mixing with an
aqueous
medium, forms a colloidal dispersion having an average particle diameter less
than
about 200 nm (e.g., less than about 150 nm) and a pH at between about 6 and
about 8.
An exemplary dry solid of the present invention may comprise about
5% to about 15% by weight alpha-tocopheryl succinate, an analogue or salt
thereof; about 3% to about 5% by weight an oil component; about 10% to about
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80% by weight sucrose; and optionally about 0.005% to about 1% by weigh edetic
acid sodium salt; wherein the dry solid, upon mixing with an aqueous medium,
forms a colloidal dispersion having an average particle diameter less than
about
150 nm and a pH at between about 6 and about 8.
In certain embodiments, the present invention provides a dry solid
that comprises about 1-15% (e.g., about 11.6%) by weight alpha-tocopheryl
succinate, about 15-35% (e.g., 28.3%) by weight lecithin, about 1-5% (e.g.,
about
3.9%) by weight cholesterol, and about 30-60% (e.g., 56.2%) by weight
cryoprotectant (e.g., sucrose); wherein the dry solid, upon mixing with an
aqueous
medium, forms a colloidal dispersion having an average particle diameter less
than
about 200 nm and a pH at between about 6 and about 8.
An example of the dry solid of the present invention may comprise
about 11.6% by weight alpha-tocopheryl succinate, about 28.3% by weight egg
lecithin, about 3.9% by weight cholesterol, and about 56.2% by weight sucrose;
wherein the dry solid, upon mixing with an aqueous medium, forms a colloidal
dispersion having an average particle diameter less than about 200 nm and a pH
at between about 6 and about 8.
Ih certain embodiments, the present invention provides a solid-in-
water colloidal dispersion comprises about 1-5% (e.g., about 3.6%) by weight
alpha-tocopheryl succinate, about 6-10% (e.g., 8.8%) by weight lecithin (e.g.,
egg
lecithin), about 0.5-2% (e.g., 1.2%) by weight cholesterol, and about 10-20%
(e.g.,
about 17.5%) by weight cryoprotectant (e.g., sucrose); wherein the colloidal
dispersion having an average particle diameter less than about 200 nm and a pH
at between about 6 and about 8.
An example of the solid-in-water colloidal dispersions of the present
invention may comprise about 3.6% by weight alpha-tocopheryl succinate, about
8.8% by weight egg lecithin, about 1.2% by weight cholesterol, and about 17.5%
by weight sucrose; wherein the colloidal dispersion having an average particle
diameter less than about 200 nm and a pH at between about 6 and about 8.
In certain embodiments, the present invention provides a dry solid
that comprises about 1-15% (e.g., about 11.5%) by weight alpha-tocopheryl
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succinate, about 15-30% (e.g., about 27.8 / ) by weight lecithin (e.g., egg
lecithin),
about 1-5% (e.g., about 3.8%) by weight cholesterol, about 30-60% (e.g., about
55.3%) by weight sucrose, and 0.5-2% (e.g., about 1.6%) by weight paclitaxel
or
docetaxel; wherein the dry solid, upon mixing with an aqueous medium, forms a
colloidal dispersion having an average particle diameter less than about 200
nm
and a pH at between about 6 and about 8.
An example of the dry solid of the present invention may comprise
about 11.5% by weight alpha-tocopheryl succinate, about 27.8% by weight egg
lecithin, about 3.8% by weight cholesterol, about 55.3% by weight sucrose, and
about 1.6% by weight paclitaxel or docetaxel; wherein the dry solid, upon
mixing
with an aqueous medium, forms a colloidal dispersion having an average
particle
diameter less than about 200 nm and a pH at between about 6 and about 8.
The pharmaceutical compositions of the invention are typically
formed by mixing alpha-tocopheryl succinate, an analogue or salt thereof and
optionally in combination with another anti-cancer agent; at least one
component
selected from the group consisting of an oil component, phospholipid,
antioxidant,
optionally cryoprotectant, and water; adjusting the pH to 5-8; homogenizing to
form
a uniform colloidal dispersion with an average particle/droplet diameter less
than
about 1000 nm (e.g., via a mechanical homogenization method including high
shear mixing, high pressure extrusion, or microfluidization); passing a
sterilizing
filter; and optionally drying the colloidal dispersion by a freeze-drying or
spray-
drying method.
In a related aspect, the present invention provides a method of
treating carcinomas comprising administering the colloidal dispersion of this
invention to a subject in need of such a treatment. The colloidal dispersions
may
be administered to animals or humans via intravascular, oral, intramuscular,
cutaneous and subcutaneous routes. Other routes of administration include, but
are not limited to, intraabdominal, intraarterial, intraarticular,
intracapsular,
intracervical, intracranial, intraductal, intradural, intralesional,
intralocular,
intralumbar, intramural, intraocular, intraoperative, intraparietal,
intraperitoneal,
intrapieural, intrapulmonary, intraspinal, intrathoracic, intratrachcal,
intratympanic,
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intrauterine, and intraventricular. The colloidal dispersions of the present
invention
may also be nebulized using suitable aerosol propellants, which are known in
the
art for pulmonary delivery of lipophilic compounds.
The general principles of the present invention may be more fully
appreciated by reference to the following non-limiting examples.
EXAMPLES
EXAMPLE 1
A 5% alpha-tocopheryl succinate dispersion was prepared
according to the conditions described in Cancel Lett. 192: 19-24, 2003 in the
following composition:
Alpha-tocopheryl succinate 5% w/w
De-ionized water to QS
NaOH to .adjust pH to 7.0
The process included the following steps:
(1) Weigh out alpha-tocopheryl succinate (Vitamin E
succinate, Product No. V1176 by Spectrum Chemicals) 4.25 mg,
(2) Add de-ionized water 56 g,
(3) Adjust pH to 7.1 using 1 N NaOH solution while stirring,
(4) Add more de-ionized water to a final concentration of
alpha-tocopheryl succinate of 5% w/w, and
(5) Apply vigorous mechanical agitation using an Ultra-Turrax
high-shear mixer to obtain a white, opaque and uniform dispersion.
The average particle diameter was measured using a laser light
scattering spectrometer (LLS, Model 370 by Particle Sizing Systems, Santa
Barbara, CA) to be 235 nm. This dispersion was kept in an airtight glass
container
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in a 5 C refrigerator for 2 weeks. Noticeable aggregation was observed in the
dispersion such as curd-like precipitates and gel-like coating adhering to the
glass
wall.
It is thus concluded that the alpha-tocopheryl succinate composition
according to CancerLett. 192: 19-24, 2003 is physically unstable and not
suited as
an injectable product for human use.
EXAMPLE 2
A 5% alpha-tocopheryl succinate dispersion was prepared
according to the following composition:
Alpha-tocopheryl succinate 5% w/w
Soybean oil 4% w/w
Medium chain triglyceride 4% w/w
De-ionized water to QS
NaOH to adjust pH to 7.0
The process included the following steps:
(1) Prepare a alpha-tocopheryl succinate dispersion using the
same procedure as in the Example 1,
(2) Add soybean oil and medium chain triglyceride to the
alpha-tocopheryl succinate dispersion, and
(3) Mixing by vigorous agitation using a Mini Beadbeater
(BioSpec) to obtain a white, opaque and uniform dispersion.
The average droplet diameter was measured using a laser light
scattering spectrometer (Model 370 by Particle Sizing Systems, Santa Barbara,
CA) to be 105 nm. This dispersion was kept in an airtight glass container in a
5 C
refrigerator for 2 weeks. No sign of degradation or aggregation was observed.
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It is thus concluded that a alpha-tocopheryl succinate composition
prepared according to the present invention that contains an oil component
(soybean oil and medium chain triglyceride) is more stable than the alpha-
tocopheryl succinate dispersion described in Example 1 according to
CancerLetter
192: 19-24, 2003.
EXAMPLE 3
A 5% alpha-tocopheryl succinate dispersion was prepared
according to the following composition:
Alpha-tocopheryl succinate 5% w/w
Soybean oil 2.5% w/w
Soy lecithin (LIPOID S-100) 2.5% w/w
De-ionized water to QS
NaOH to adjust pH to 7.0
The process included the following steps:
(1) Prepare a alpha-tocopheryl succinate dispersion using the
same procedure as in the Example 1,
(2) Add soybean oil and Soy lecithin to the alpha-tocopheryl
succinate dispersion, and
(3) Mixing by vigorous agitation using a Mini Beadbeater
(BioSpec) to obtain a white, opaque and uniform dispersion.
The average droplet diameter was measured using a laser light
scattering spectrometer (Model 370 by Particle Sizing Systems, Santa Barbara,
CA) to be 213 nm. This dispersion was kept in an airtight glass container in a
5 C
refrigerator for 2 weeks. No sign of degradation or aggregation was observed.
It is thus concluded that a alpha-tocopheryl succinate composition
according to this invention that contains an oil component (soybean oil) and
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phospholipid (soy lecithin) is physically and chemically more stable than the
alpha-
tocopheryl succinate dispersion described Example 1 according to Cancer Lett.
192:19-24, 2003.
EXAMPLE 4
The dispersions prepared in Example 1, 2 and 3 were compared
for their capability of carrying an insoluble anti-cancer agent, i.e.,
paclitaxel.
The study was conducted as follow:
(1) Into each dispersion (1000 mg) add 0.5 mg Paclitaxel
(SiChuan KangYi Corp, China);
(2) Mixing by vigorous agitation using a Mini Beadbeater
(BioSpec) to obtain a white, opaque and uniform dispersion and then rotate the
dispersion at room temperature for 16 hours,
(3) Filter each dispersion through a 0.2 micron size syringe
filter, and
(4) Dilute the filtrate and perform an HPLC analysis for
Paclitaxel concentration in the filtrate.
Results
Formulation Paclitaxel concentration
(mg/mL)
Dispersion in Example 1 0.19
Dispersion in Example 2 0.39
Dispersion in Example 3 0.26
It is thus concluded that alpha-tocopheryl succinate compositions
according to this invention, i.e., with an oil component (Example 2) or with
both oil
component and phospholipid (Example 3), are capable of carrying significantly
more insoluble anticancer drug Paclitaxel than the alpha-tocopheryl succinate
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dispersion described in Example 1 according to Cancer Lett. 192: 19-24, 2003,
while maintaining good stability.
EXAMPLE 5
Another alpha-tocopheryl succinate dispersion according to this
invention was prepared to contain 3.6% alpha-tocopheryl succinate, and
optionally the insoluble anticancer drug Paclitaxel according to the following
compositions:
Alpha-tocopheryl succinate 3.6% w/w
Paclitaxel 0.5% w/w (optional)
Egg lecithin (LIPOID E80) 8.8% w/w
Cholesterol 1.2% w/w
Sucrose 17.5% w/w
De-ionized water to QS
NaOH/HCI to adjust pH to 7.0
The preparation of an oil phase was performed as follows:
(1) Weigh out, egg lecithin and cholesterol, and optionally
paclitaxel or docetaxel all in one container,
(2) Add enough anhydrous ethanol to dissolve all solids and
obtain a clear yellow solution, and
(3) Apply rotary vacuum drying to remove ethanol completely
to obtain a semi-solid oil phase.
The preparation of a alpha-tocopheryl succinate colloidal
dispersion was performed as follows:
(1) Weigh out the oil phase, sucrose and alpha-tocopheryl
succinate, all in one container,
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(2) Apply a vigorous mechanical agitation using an Ultra-
Turrax high-shear mixer for 5 minutes to obtain a crude colloidal dispersion,
(3) Pass the crude colloidal dispersion through a microfluidizer
(Model 110F by Microfluidics, MA) operating at 18000 psi pressure six times to
obtain a translucent, slightly yellow colloidal dispersion, and
(4) Filter the microfluidized dispersion through a 0.2 m
membrane filter.
The average colloidal dispersion droplet diameter was measured
using a laser light scattering spectrometer (Model 370 by Particle Sizing
Systems,
Santa Barbara, CA) to be 120-130nm.
The preparation of a alpha-tocopheryl succinate solid-in-solid
dispersion by freeze-drying was performed as follows:
(1) The filtered colloidal dispersion was filled at 0.9 mL into each
2 mL glass vial and was freeze-dried using a Virtis Advantage Freeze-drierto
form
uniform white mass (a solid-in-solid dispersion), and
(2) Add deionized water to the solid-in-solid dispersion and mix
gently to obtain a translucent slightly yellow dispersion (a solid-in-water
dispersion).
The average droplet diameter of the reconstituted alpha-tocopheryl
succinate dispersion was measured using a laser light scattering spectrometer
(Model 370 by Particle Sizing Systems, Santa Barbara, CA) to be 120-130 nm.
The alpha-tocopheryl succinate solid-in-solid dispersion was kept in an
airtight
glass container in a 5 C refrigerator for 4 weeks. No degradation and
aggregation
was observed.
It is thus concluded that a solid-in-solid alpha-tocopheryl succinate
colloidal dispersion according to this invention can be prepared with
optionally an
insoluble anticancer drug Paclitaxel. The compositions prepared in this
example
are stable.
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EXAMPLE 6
HEMOLYSIS TEST
Two alpha-tocopheryl succinate dispersions were prepared
according to this invention to contain the following compositions:
Alpha-tocopheryl succinate 5% w/w
Egg lecithin (LIPOID E80) 5% w/w
De-ionized water to QS
NaOH/HCI to adjust pH to 7.0
Alpha-tocopheryl succinate 5% w/w
Soybean oil 2.5% w/w
Egg lecithin (LIPOID E-80) 2.5 w/w
De-ionized water to QS
NaOH/HCI to adjust pH to 7.0
Both dispersions were tested for hemolysis using rabbit blood.
Rabbit red blood cells (2%) were suspended in normal saline and were mixed
with the test articles as follow:
Test tube 1 2 3 4 5 6 7
2% RBC suspension, 2.5 2.5 2.5 2.5 2.5 2.5 2.5
mL
Normal saline 2.4 2.3 2.2 2.1 2.0 2.5 0
(negative control), mL
alpha-tocopheryl 0.1 0.2 0.3 0.4 0.5 0 0
succinate dispersion,
mL
Distilled water 0 0 0 0 0 0 2.5
(Positive control), mL
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The test tubes were kept at 37 C and were observed for hemolysis
(when the supernatant becomes red). Test tube 7 showed hemolysis. Neither
alpha-tocopheryl succinate dispersion showed sign of hemolysis in 2 hours. It
is
concluded that the alpha-tocopheryl succinate dispersions according to this
invention are not hemolytic and are suitable for injection.
From the foregoing it will be appreciated that, although specific
embodiments of the invention have been described herein for purposes of
illustration, various modifications may be made without deviating from the
spirit
and scope of the invention. Accordingly, the invention is not limited except
as by
the appended claims.
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